Sustaining device for vapor-converters.



S. W. FARNSWORTH.

SUSIMNING DEVICE FOR VAPOR CONVERTEHS.

APPLICATION man 1uLv14, 1915.

1,227,766.. f Patented May 29, 1917.

INVENTOR WITNEssEs UNITED sTATEs PATENT oEEIoE.

sInNEY w. rAnNswon'rn, or rrr'rsnunen, rENNsYLvmL AsslGNon To Waermenousn Ennemis AND uANUrnc'rUaINe COMPANY, A oonrom'riou or PENNSYL- VANIA.

sus'iulnvnvuiV DEVICE ron varon-convnn'rmas. I

Patented May 2a, 1917'.

appiiemon ma my i4, isis. serial in. sam.

To'alZ 'whom it may concern.'

Be it known that I, SIDNEY W. FAnNs- WORTH a citizen of the United Stateaand a resident of Pittsburgh in the county of Allegheny and State o liennsylvania, have invented a new -and useful Improvement in Sustaining Devices for Vapor-Converters,

of which the following is a specification.

My invention relates to arc-sustaining dei In the operation of vapor converters of` the type wherein alternating current is converted into unidirectional current, it is necessary to provide a sustaining or keep-alive anode to energize thecathode at times when the supply circuit is inactive. This sustaining device has hitherto commonly taken the form of a refractory conducting rod extending into the converter to a point adjacent the surface of the cathode and connected to a suitable source of exciting current, either direct or alternatin with such phase relation to the 'supply t at a keepalive arc is maintained at all times when the main converting arc would tend to go out. Suitable means are provided for initiating .an arc between the keep-alive electrode and the cathode,` either by. causing the two to. make and break contact 'or by impressing a Ihighl voltage therebetween. In a vapor converter of large capacity, lthe cathode is necessarily provided with an extended activeV cathode surface and the cathode end of a keep-alive arc .tends to wander in an erratic manner over this surface. As the 4upper end of the lkeep-alive are is necessarily more or less fixed in position upon Vthe lower portion of the keepalive anode, the keepalive arc varies in length and in voltage consump-V greatly When the keep-alive are:` has a tion.

' minimum length, the potential consumed thereby need not exceed *10 orv 15 volts whereas, if the ar'cis drawn out to a con.- siderable length, it may easily consume as much as 30 volts.

extending over the entire active portion thereof. The perforations in said plate are of such size .that the main converting arc may flow therethrou h without diliiculty. A keep-alive' electro e of the usual form projects through one of the perforations in in the said manner and said keep-alive electrode is 'furthermore' connected, either within or without the container, to said perforated plate. By this i struct-ure, .the keep-alive arc, when initiated, readily transfers itself to the plate and the tendency `to wandering atthe cathode end of the keep-alive arc tends to move the entire arcI about on the surface of the cathode, a minimum length being substantially maintained at all times.

ing'- only sufficient voltage to supply the minimum amount consumed 'by t e keepalive arc, unnecessary resistance and relsultan't waste vis eliminated, little or no lattention is necessary, .and the keep-alive late outlives. the converter because .of its argecross section and heat-radiatingy capacity.

Referring to the accompanyingdraw'ing' for a more detailed understanding of my invention, I show a vapor converter of the usual type provided Vwith a' container V1, a main anode 2 and a cathode 3, the latter composed 'ieferably cf mercury. Akeepalive anoV e 4. of the usual ty eprojects.

through the cover of the container 1 and is insulated therefrom by suitable means 5'. The' keep-alive anode 4 terminates a shortl-dstanoeabove the cathode ,3, prefer- It is therefore necessary to provide a source of keep-alive circuits ha'v- It has therefore been necessary hitherto to provide a kee -alive said plate so that the arc4 may be initiated .direct emission of mercury g ably in a tip 6 composed of a refracto'ry material, such, for example, as tungsten. The keep-alive anode 4 is shielded from the main power arc by a suitable shell 7 and is energized from a source 8 through an adjustable rheostat 9. An arc-controlling ring 10 composedof refractory insulating uartz or material, such, for example, as

portion P porcelain, is laced in the centra of the 'catho e 3 and su ports a ate or grid 11 on its upper e' ge, said late or grid bein prefers ly composed o refractory con uctiiig material, such, for examle, as cast iron or stamped steel. The iieep-alive 4anode 4 projects through one Aof the perforations in the plate 11 and is connected thereto by a flexible connecting de` vice 12.

Having thus describedthe structure of a converter embod ing my invention, the o eration is as fo lows: At the outset, t e keep-alive arc is struck between the tip 6 and the cathode 3, either by successively lowering and raising the keep-alive anode 4 by asuitable operating device (not show-n) or by slo 'ping or splashing the cathode malength will be provided. Anyy subsequentniovement of the p`oint 13 will be followed by a like movement of the oint 15 and thus the entire kee -alive arc will .move about-on the surface o the cathode.

.I may, if desired, withdraw the anode 4 through the grid 11 in starting, thus causing the keep-alive arc to operate solely from said grid. Furthermore, I may so modify-- the grid 11 'that it serves the additionalfunction` of acathodeshield, reventing the Icbules against the anode, but modifications of this character form no part of the present invention and are covered in separate applications.

An extremely valuable feature of my invention exhibits itself in converters designed for railway use wherein the cathode 3 is sub'ect' to continual splashing and vibration an `whereit is therefore essential that the keep-alive electrode be disposed at much greater distance from the cathode than would otherwise be nry. 'Were' the tip 6 to be raised to the necessary hei ht, an excessively lo path for thekee -a ive arc would be pr uced if the spot 1 wandered away from-its preferred position. By

Vdisposing a 'd 11 at the desired height above the cat ode 3, an arc length may be chosen which has minimum values for safety from extinguishment from splashing but which, at the same time, does not demand an excessive] high yoperating voltage.

While have shown my invention in its preferred form, it will be obvious to those skilled in the art that it is susceptible of various minor changes and. modifications without departing from the spirit thereof, and I desire,therefore, that no limitations shall be placed thereupon except such as are imposed by the prior art or are specifically set forth in the appended claims.

I claim as my' invention:

1. In a vap'or electric device, the combination with al cathode, of a' kee -alive anode substantially coextensive with t e active surface thereof, said keep-alive anode bein provided with openings for the assa e o the converting arc to any part of t e cat ode surface. p

2. In a vaporelectric device, the-combina'- tion with a cathode, of` a kee -alive anode extending over substantially t e entire active surface thereof, but so perforated as to active surface, of a reticulated ke` -alive anode provided with portions exten ing in over substantially the entire aci proximity. to all portions -of said cathode surface.

5. In ava'por'electric device, the combination with a liquid cathode having an extend- 'ed active surface, of a reticulated conducting plate adjacent, substantially arallel. to and coe'xtensive with, saidc'atho e surface,

and connections from said plate to a keepalive circuit, whereby said plate is adapted to o erate as a keep-alive anode. Q 6. a vapor electric device, the combination with a liquid cathode having an extended active surface, of a reticulated conducting late adjacent, substantially arallel to and)coextensve with, said cath e'surface, a keep-alive anode extending through said plate and into proximity to said cathode, and a connection from said keepalive anode to said plate, Awhereby a kee alive arc initiated by said anode may transferred to, and operated from, any portion of said plate.

7. The combination with a vapor electric deviceprovided with main electrodes and a, retioulated keep-alive anode, of means for causing the main convertlng arc to operate 'through the perforations in said anode.

"8. AThe combination with a vapor electric i device provided v vith an extended cathode, of means for permitting the'keep-alive arc to follow the main cathode spot while maintaining a substantially uniform predetermined length.

g In testimony whereof, I have hereunto subscribed my ,namethis 28th day of June SIDNEY W. FARN'svvoiz'rl4 

